1. Field of the Invention
The present invention generally relates to the field of user input devices for computers; more particularly, to user input devices for computers comprising a projected keyboard and apparatus for detecting user input using electromagnetic signals.
2. Description of the Prior Art
In recent years, the size of portable computers have significantly decreased from the original laptop design, to the handheld and sub-notebook computers. Hand-held computers and sub-notebook computers are smaller computers with a laptop type configuration. Even though handheld and sub-notebook computers that use keyboards are small (e.g., About 3.5″×7″×1″ for handheld, and about 4.5″×8″×1.5″ for sub-notebook computers), they provide essentially the same functionality of larger computers. For instance, handheld and sub-notebook computers run productivity software including word processors, spreadsheets, fax, email, etc, and can communicate and replicate information with other computers using wireless or wired connections. Because of the rapid advancement of computer technology, the capabilities of these smaller computers are constantly increasing. However, there are problems associated with these smaller computers that have been hindering their effectiveness in spite of increasing processing power and an expanding selection of productivity software.
First, regardless of the capability of the hardware and the availability of software for these small computers, their functionality is constrained because they have keyboards that are too small to use effectively and comfortably. In order to use the available productivity software, full keyboard function is essential. Therefore, manufacturers have been attempting to integrate full physical keyboards into the footprint area of these small computers. Typically, this means that the keys are small, closely spaced, and some single-key functions are accessed through complex key combinations. Resulting layouts are packed with too many keys that are too cramped to allow adequate keyboard input. Not only are these keyboards tedious to use, they are a bottleneck and pose a significant barrier to attaining the potential functionality for handhelds and sub-notebooks that manufacturers are trying to provide and that consumers want. As miniaturization and processors continue to improve, ease of input and effective display area will be increasingly critical factors constraining the use and functionality of handheld and sub-notebook computers.
There have been varying efforts to address these problems. For instance, U.S. Pat. Nos. 5,687,058; 5,187,644; 5,267,127; 5,543,787; 5,706,167; 5,644,338; 6,111,527 disclose physical apparatuses in varying dimensions enabling for easier transportation and storage. Some of these patented keyboard designs are foldable in order to reduce dimensionality, however, result in a bulkier design and lack functionality until the keyboard is unfolded.
Different standards for keyboard layout are another constraint of physical keyboards. For instance, computer users requiring Chinese characters may prefer a smaller keyboard, using only 24 keys. Alternately, users working with a standard layout, such as the QWERTY keyboard layout, want to switch to another standard layout, such as the Dvorak keyboard layout, to increase typing efficiency. When working on a spreadsheet, users will prefer to have a numerical keypad available.
Thus, it is the case that the layout of the keyboard needs to change in the amount and location of the keys, as well as the image on the keys which refers to the action initiated by pressing the key. Unfortunately, conventional techniques for changing keycaps, such as described in U.S. Pat. No. 5,387,042 for a Multilingual Keyboard System, or W.O. Patent 26759, change only the image on the keys without providing the option to change the number or location of these keys. For instance, children might benefit from a simplified keyboard with large keys. Users working with a numerical keypad for a longer period will have an ergonomical need to change the position of the keys on the keyboard, to alternate their movements and position.
Many companies are currently considering options for these input devices. One solution in the art for inputting characters to small computing devices include the use of a virtual reality glove which incorporates an RF transmitter for wireless input. For instance, as described at
http://bsac.eecs.berkeley.edu/˜shollar/fingeracc/fingeracc.html, an acceleration sensing glove equipped with accelerometers placed at each finger may be used to interpret hand/finger gestures representing characters or symbols that may be interpreted by a computer and generate signals for wireless transmission to a computing device. While a viable solution, it requires the user to be fitted with the glove and become familiar with all of the numerous hand gestures representing the characters.
Furthermore, technology described at
http://www.ad.n1/artikelen/InternetenPc/1007014756653.html enables users of personal digital assistants (i.e., Palm) to type in front of the computing device, without a physical keyboard as such being available. The result is achieved by two devices being mounted on the user's hands that detect finger movement by rubber extensions. One disadvantage of this system is that the user has to type blind, i.e., the user does not have a view of the keyboard at the place where the user types. The signal from the rubber extensions is translated into position and sent wireless (e.g., by using Bluetooth technology) to the computing device. This technology still uses devices outside of the computing device itself, the position of the pressed key being detected physically with rubber extensions with no image of the keyboard being displayed.
Thus, there is a need in the art for a customizable keyboard assembly for handheld and sub-notebook computers, which provides the effectiveness and comfort of a full-size keyboard without significantly affecting the size or weight of the computer.